This invention relates to portable striking tools, in particular, to a drywall striking tool.
In building construction using drywall (paper-encased gypsum core) panels, the panels are attached to supports, such as studs, by nails or other suitable fasteners. Professional drywall installers frequently use a specialized, relatively lightweight, striking tool for the nailing. One type of tool is termed a drywall (or wallboard) hatchet or hammer, and is designed for use in the installation of room wall and ceiling panels which are to be covered with a paint finish or the like, that does not hide surface irregularities. The drywall hatchet has a head unit which includes a medial body portion, a hammerhead portion projecting forwardly therefrom, and a blade portion projecting rearwardly therefrom. The hammerhead portion is symmetrical and disk-like in shape, and has a convex, or "crowned", striking surface, or face, for driving nails. Blunt serrations are provided in the central area of the striking surface, and a smooth border is provided therearound. The margin of the hammerhead portion is smooth and rounded. The blade portion is shaped like a hatchet blade or wedge and it is intended for cutting and/or wedging and prying panels.
The foregoing drywall hatchet facilitates the installation of panels in a manner such that they readily can be prepared so as to provide a smooth, flat surface suitable for painting. The convex striking surface of the hammerhead portion slightly compresses the gypsum core of the panel when the final blow of the tool is struck, to form a dimple or shallow concave depression in the panel surface. The nailhead is seated in the dimple and covered with filler, such as a drywall joint compound, and the surface of the panel is levelled. The serrations in the striking surface serve to grip the nailhead and to impress a waffle-like pattern on the surface of the dimple, which assists in holding the filler. The possibility of marring the surface of the panel by breaking or puncturing its paper facing is minimized for hammer blows which are square, or normal, to the panel surface, owing to the curvature of the striking surface, the bluntness of the serrations, and the smoothness of the border. The possibility of damage to the paper caused by an edgewise blow of the hammerhead portion is minimized by the smoothness of the border, the absence of serrations at the margin, and the roundness of the margin.
While the foregoing drywall hatchet is generally satisfactory for nailing panels, difficulties arise when it is used to drive a nail close to the intersection of two room surfaces, as, for example, at a wall-ceiling, wall-floor, and/or wall-wall junction. At such a location, the above-described configuration of the hammerhead, which lessens the chance of marring the panel surface, also makes it difficult to strike a blow with the striking surface square to and fully engaging the nailhead. A nail hit a glancing blow on the head frequently is bent, so that the nail either must be straightened before being driven in completely, or must be removed and replaced with a straight nail. Either course of action increases the possibility of damage to the panel and the installation time, with resulting increase in the cost of installation.
Other striking tools used in drywall panel installations include lathing hatchets, particularly those of the "Underhill" design. These tools are designed for installation of panels intended for surfacing with thick coatings, such as plaster, which conceal surface irregularities. The heads of nails used in such installations are, conventionally, driven flush with the panel surface rather than into a dimple in the surface.
The Underhill lathing hatchet has a head unit construction which allows it to be used for driving nails in close proximity to the junction of several surfaces. However, the construction of the striking surface of the lathing hatchet makes it relatively unsuitable for use in installing drywall panels which are to be finished by painting or similar methods. Thus, the lathing hatchet has a hammerhead portion which is substantially square in shape and has generally flat top, side, and bottom surfaces. The top surface is substantially coplanar with the top surfaces of the hatchet body and blade portions. These characteristics allow the hammerhead portion to strike nails close to an adjoining surface. However, the striking surface has relatively sharply pointed serrations, and the serrations extend close to the several flat surfaces. The latter characteristics of the lathing hatchet make it difficult to form a dimple in the surface of a drywall panel without breaking or puncturing its paper facing.
Other tools have hammerhead portions which resemble the hammerhead portion of the lathing hatchet and suffer from the same deficiencies. They include box, roofing, and shingling hatchets.